Established Series


The Verhalen series consists of very deep, moderately well drained, very slowly permeable soils formed in calcareous clayey alluvium. These soils are on nearly level to very gently sloping alluvial flats, valleys, and basin floors. Slopes range from 0 to 3 percent.

TAXONOMIC CLASS: Fine, smectitic, thermic Typic Haplotorrerts

TYPICAL PEDON: Verhalen clay--rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 10 inches; grayish brown (10YR 5/2) clay, very dark grayish brown (10YR 3/2) moist; weak very fine granular structure; very hard, very firm, very sticky, and moderately plastic; common fine roots; few fine pores; cracks 1 inch wide extend to lower boundary; slightly effervescent; moderately alkaline; gradual wavy boundary. (8 to 18 inches thick)

Bss--10 to 43 inches; brown (7.5YR 4/2) clay, dark brown (7.5YR 3/2) moist; moderate medium angular blocky structure; very hard, very firm; few fine roots; few very fine pores; common distinct slickensides; cracks 0.5 inch wide extend to lower boundary; few concretions of calcium carbonate; few crystals and masses of calcium sulfate; strongly effervescent; moderately alkaline; diffuse wavy boundary. (12 to 40 inches thick)

BCk--43 to 80 inches; pink (5YR 7/4) clay, light reddish brown (5YR 6/4) moist; massive; very hard, very firm; 5 percent masses and fine concretions of calcium carbonate; few fine crystals and masses of calcium sulfate; few fine igneous gravel; violently effervescent; moderately alkaline.

TYPE LOCATION: Reeves County, Texas; from the intersection of U.S. Highway 290 and Texas Highway 17 in Pecos; 3.95 miles east on U.S. highway 290; 200 feet south of the center line of U. S. Highway 290, this being the northeast corner of Section 172, Block 13, H & GN RR Survey. Latitude: 30 degrees, 58 minutes, 50 seconds, North; Longitude: 103 degrees, 35 minutes, 43 seconds West.


Soil moisture regime - Intermittently moist in some part of the soil moisture control section during July-September and December-February. Driest during May and June. The epipedon is moist in some part less than 90 days cumulative per year. Ustic aridic moisture regime.

Solum thickness - greater than 80 inches.

Cracks - range from 0.5 to 2 inches wide and 12 inches or more long that extends from the surface or the lower boundary of the Ap horizon to depths of 30 to more than 40 inches and are open most of the time if the soil is not irrigated.

Effervescence - ranges from calcareous to noncalcareous in the upper 12 inches, and is calcareous below this depth. Some pedons have calcic horizons below 40 inches.

Electrical conductivity - ranges from 0 to 8 dS/m.

Reaction: neutral to moderately alkaline

A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 3 to 5 dry, 2.5 or 3 moist
Chroma: 2 to 4. More than half of each pedon, to a depth of 12 or more inches, has chroma of less than 3 moist or dry.
Texture: clay, clay loam, silty clay, silty clay loam
Clay content: ranges from 35 to 60 percent
Rock fragments: 0 to 65 percent of which 0 to 25 percent are gravel, and 0 to 45 percent cobbles

Bss horizon
Hue: 5YR, 7.5YR, 10YR
Value: 3 to 6 dry, 2 to 4 moist
Chroma: 1 to 4, dry or moist
Texture: clay loam, silty clay or clay, averaging 35 to 60 percent clay.
Visible calcium carbonate in the form of films, threads and masses that ranges from few to common.
Calcium carbonate equivalent: 5 to 35 percent, but averages 15 percent or less in more than half of all pedons.
Other features: If Bss horizon is at 12 inches or less, the chroma is less than 3.

BCk horizon
Hue: 5YR, 7.5YR
Value: 5 to 7, dry or moist
Chroma: 2 to 4, dry or moist
Texture: clay, silty clay or clay loam
Clay content: 35 to 60 percent clay
Rock fragments: none to few fine pebbles
Visible calcium carbonate: in the form of films, threads and masses, range from common to many.
Calcium carbonate equivalent: 5 to 35 percent

COMPETING SERIES: This is the Bonita (AZ) series. Bonita soils have buried paleosols at 25 to 40 inches.

GEOGRAPHIC SETTING: Verhalen soils are on alluvial flats, valleys, and basin floors in a mountain and bolson landscape. These soils have gilgai microrelief, and the surfaces are plane to concave. Slopes are dominantly less than 1 percent, but range to 3 percent. The soil formed in calcareous clayey alluvium several feet thick. Mean annual precipitation ranges from 10 to 16 inches, and the mean annual air temperature ranges from 62 to 69 degrees F. Frost-free period ranges from 210 to 250 days, and elevation ranges from 2,500 to 5,500 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Balmorhea, Dalby, Phantom, Redona, and Toyah series. Balmorhea, and Toyah soils have less than 35 percent clay and do not have cracks and gilgai. Phantom soils do not have slickensides. All associated soils, are in similar positions on the landscape.

DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is very slow. Runoff is high on slopes less than 1 percent and very high on slopes from 1 to 3 percent. The soil ponds water for 2 to 7 days following high intensity rains, mainly during July through October.

USE AND VEGETATION: Irrigated cropland, livestock grazing and wildlife habitat. Native vegetation is tobosa grass, buffalo grass, blue and black grama, mesquite shrubs, catclaw, and Texas varilla.

DISTRIBUTION AND EXTENT: West Texas and Southern New Mexico. MLRA 42. The series is of moderate extent.


SERIES ESTABLISHED: Reeves County, Texas; 1922.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon - the zone from 0 to 43 inches (A and Bss horizons)

Vertic properties - the soil has cracks that open and close periodically, and has slickensides

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

Update and revisions for Recorrelation of Brewster County, Texas, Main Part, 2/12/08, CEM

Revised for the correlation of Hudspeth County, Texas (Main Part) and Culberson County, Texas (Main Part); July, 2012, NMS

Revised for the correlation of Presidio County, Texas ; Oct, 2012, WWJ

ADDITIONAL DATA: Lincoln Laboratory data available for 1 pedon from Reeves County, Texas. Sample No. 71L1370.

National Cooperative Soil Survey